So, I ask them, why does the 747 have an upstairs cabin? Because Boeing planned it that way, they answer. They are quite wrong, but the example of the 747 is useful because it points to some ...

English heavy metal band Iron Maiden once sang, “Bring Your Daughter to the Slaughter,” but when it comes to dismantling the band’s Boeing 747-400 tour plane, it’s a little more complicated.